Aftermarket headunit question

[LSsoFresh]

I just installed an Alpine iva-w200, and my door speakers are playing my highs but i hear no lows. I was told that i need a wire harness adapter for the stock subs. Does any one know what piece i need and where i can get? Thanks

-CAsh

 

[Frogman]

Any Stereo shop should be able to get you the correct harness.